EAF-Nansen Programme

Leg 2. Transboundary Demersal Survey (southwest Africa)

Period: 28 February 2019 - 16 July 2019  (118 days)
Countries:
Port of departure: Cape Town (South Africa)
Port of arrival: Tema (Ghana)

This survey originally included six legs, with Congo-Gabon survey (leg 2.6) that had to be replaced by an oceanographic transect across the Gulf of Guinea. Legs 2.1-2.5 were carried out to cover the demersal resources of the continental shelf and upper slope including distribution, abundance and biology of priority species and communities. The objective was also to collect biological samples of priority species, determine oceanographic conditions and map the occurrence of microplastics and marine debris.

Leg 2.3 was a mesopelagic transect survey aimed to study acoustic properties of mesopelagic fish, biology and collect samples for future analysis of mesopelagic fish and jellyfish off the coast of Namibia.

  • Leg 2.1. Transboundary Demersal Survey (south Africa) 
    Period28 February – 31 March (30 days)
    Survey Type: Transboundary Demersal Survey
    Port of departure:
    Cape Town (south Africa)
    Port of arrival: Walvis Bay (Namibia)
    Local participants: 15 (8 women)
    Participants from Norway: 8
    International participants: 0

    The objective of this leg was to cover the west coast of South Africa from 20 to 800 meters depth, from the south (20 degrees east) to the border with Namibia. Continuation of the transboundary demersal time-series for the West Coast of South Africa and Namibia.

    More specific objectives included:

    • To map the hydrographic/environmental conditions in the survey area (temperature, salinity, oxygen, chlorophyll, nutrients and pH values-acidity). Obtain information on the oxygen concentrations and ocean acidification state and calcium carbonate saturation horizon, relevant for calcifying organisms;
    • To describe the abundance and biomass patterns of meso-zooplankton community, as well as its species composition;
    • To provide information on the abundance patterns of ichthyoplankton community (fish eggs and larvae), at the lowest possible taxonomic level;
    • To collect samples of jellyfish;
    • To study the distribution, abundance and and stock structure of selected species – hake (both species), monkfish, kingklip;
    • To carry out fecundity studies – hake (both species);
    • To study juvenile hake species identification and distribution;
    • To carry out benthic studies: collection of benthic invertebrate data for species identification and species composition;
    • To opportunistically collect samples of Cape horse mackerel (Trachurus capensis) and Scomber colias for genetic analysis;
    • To map occurrence of microplastics and describe associated neustonic communities.
  • Leg 2.2. Transboundary Demersal Survey (south Namibia)
    Period: 4 – 24 April (20 days)
    Survey TypeTransboundary Demersal Survey
    Port of departure: Walvis Bay (Namibia)
    Port of arrival: Walvis Bay (Namibia)
    Local participants: 16 (8 women)
    Participants from Norway: 6
    International participants:
     0

    The objective of this leg was to cover the Orange Banks (to the depth of 1000 meters) for detailed mapping of the oceanographic conditions that are of importance for the distribution of juvenile M. paradoxus off the west Coast of south Africa.

    More specific objectives included:

    • To map the hydrographic/environmental conditions in the survey area (temperature, salinity, oxygen, chlorophyll, nutrients and pH values-acidity). Obtain information on the oxygen concentrations and ocean acidification state and calcium carbonate saturation horizon, relevant for calcifying organisms;
    • To describe the abundance and biomass patterns of meso-zooplankton community, as well as its species composition;
    • To provide information on the abundance patterns of ichthyoplankton community (fish eggs and larvae), at the lowest possible taxonomic level;
    • To collect samples of jellyfish;
    • To study the distribution, abundance and and stock structure of selected species – hake (both species), monkfish, kingklip;
    • To carry out fecundity studies – hake (both species);
    • To study juvenile hake species identification and distribution;
    • To carry out benthic studies: collection of benthic invertebrate data for species identification and species composition;
    • To opportunistically collect samples of Cape horse mackerel (Trachurus capensis) and Scomber colias for genetic analysis;
    • To map occurrence of microplastics and describe associated neustonic communities.
  • Leg 2.3. Mesopelagic transect
    Period
    27 April – 7 May (11 days)
    Survey Type: Mesopelagic Transect
    Port of departure:
    Walvis Bay (Namibia)
    Port of arrival: Walvis Bay (Namibia)
    Local participants: 15 (8 women)
    Participants from Norway: 0
    International participants: 1

    The overall objective of the survey was to study the acoustic properties and biological composition of the mesopelagic community along a transect spanning from inshore eutrophic coastal waters off southwest Africa towards the eutrophic oceanic waters, but it also included studies of the oceanography and plankton and jellyfish. 

    Specific objectives of the different studies were to:

    Mesopelagic community

    • Obtain concurrent information on the acoustical properties and biological composition of the mesopelagic community
    • Study the acoustic properties of mesopelagic fish and other mesopelagic organisms such as squids, crustaceans, gelatinous organisms and principal zooplankton taxa including their frequency response and target strength
    • Obtain biological samples and observations using different sampling gears (trawls, plankton nets and camera systems)
    • Investigate the effectiveness of different sampling trawls used to sample the mesopelagic community 
    • Collect samples for analysis of C and N stable isotope ratios and fatty acid composition to understand the trophic roles of mesopelagic species 
    • Collect samples for levels of nutrients and contaminants including microplastics, parasites and microorganisms with regards to food safety and pollution


    Oceanography

    • Map the hydrographic/environmental conditions in the survey area (temperature, salinity, oxygen, fluorescence, irradiant light, nutrients and pH)
    • Measure the principal current dynamics across the shelf, slope and basin
    • Estimate the productivity along the inshore-offshore eutrophication gradient 


    Plankton and jellyfish

    • Describe the broad distribution, abundance and taxonomic composition of jellyfish and zooplankton

  • Leg 2.4. Transboundary Demersal Survey (north Namibia and Southern and Central Angola) 
    Period11 May – 10 June (30 days)
    Survey Type:
    Transboundary Demersal Survey
    Port of departure:
    Walvis Bay (Namibia)
    Port of arrival: Luanda (Angola)
    Local participants: 20 (7 women) 
    Participants from Norway: 7 
    International participants: 1

    The objective of this leg was to cover transboundary demersal resources between Namibia and Angola.

    More specific objectives included:

    • To map the hydrographic/environmental conditions in the survey area (temperature, salinity, oxygen, chlorophyll, nutrients and pH values-acidity). Obtain information on the oxygen concentrations and ocean acidification state and calcium carbonate saturation horizon, relevant for calcifying organisms;
    • To describe the abundance and biomass patterns of meso-zooplankton community, as well as its species composition;
    • To provide information on the abundance patterns of ichthyoplankton community (fish eggs and larvae), at the lowest possible taxonomic level;
    • To collect samples of jellyfish;
    • To study the distribution, abundance and and stock structure of selected species – hake (both species), monkfish, kingklip and large-eye dentex;
    • To carry out benthic studies: collection of benthic invertebrate data for species identification and species composition;
    • To opportunistically collect samples of Cape horse mackerel (Trachurus capensis) and Scomber colias for genetic analysis;
    • To map occurrence of microplastics and describe associated neustonic communities.
  • Leg 2.5. Transboundary Demersal Survey (Angola)  
    Period: 13 – 27 June (14 days)
    Survey Type:
    Transboundary Demersal Survey
    Port of departure:
    Luanda (Angola)
    Port of arrival: Pointe Noire (Gabon)
    Local participants: 18 (7 women)
    Participants from Norway: 6
    International participants:
     0

    The main objective of this leg was to survey transboundary demersal species in south-eastern Atlantic with special emphasis on the species shared between Angola, the Democratic Republic of Congo (DRC), The Congo and Gabon. Unfortunately this leg could only cover Northern Angola and DRC because of security issues.

    Specific objectives included:

    • To map the hydrographic/environmental conditions in the survey area (temperature, salinity, oxygen, chlorophyll, nutrients and pH values-acidity). Obtain information on the oxygen concentrations and ocean acidification state and calcium carbonate saturation horizon, relevant for calcifying organisms;
    • To describe the abundance and biomass patterns of meso-zooplankton community, as well as its species composition;
    • To provide information on the abundance patterns of ichthyoplankton community (fish eggs and larvae), at the lowest possible taxonomic level;
    • To collect samples of jellyfish;
    • To study the distribution of the demersal community and the abundance of selected species;
    • To carry out benthic studies: collection of benthic invertebrate data for species identification and species composition;
    • To map occurrence of microplastics and describe associated neustonic communities.
  • Leg 2.6. Oceanographic Survey (Gulf of Guinea)
    Period: 29 June – 16 July (17 days)
    Survey Type: Oceanographic Survey
    Port of departure:
    Luanda (Angola)
    Port of arrival: Tema (Ghana)
    Local participants: 17 (5 women)
    Participants from Norway: 8
    International participants: 0

    The main objectives of this leg were to:
    • Investigate transition from the Angolan upwelling to the open ocean and from the open ocean to coastal upwelling off Ghana - Côte d’Ivoire;
    • Investigate the northern perimeter of the Angola Dome and Angola Gyre;
    • Determine physical, chemical and biological characteristics of the Equatorial Under Current (EUC) and equatorial upwelling;
    • Investigate the northern transition between the Equatorial Cold Tongue and the westward current system in the central Gulf of Guinea.